Boat and control method for same

ABSTRACT

A sensor detects a shape of a shore arrival location and a positional relationship of the shore arrival location and a boat body and outputs environment information indicating the shape of the shore arrival location and the positional relationship. A controller receives the environment information and generates an instruction signal to control a propulsion device to cause the boat body to move toward the shore arrival location based on the environment information and to push the boat body to the shore arrival location.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a boat and a control method for theboat.

2. Description of the Related Art

The smooth shore arrival of a boat requires high skill and is not easyfor anyone except an experienced person. Accordingly, a device forassisting the arrival of a boat at the shore is conventionally known.For example, Japanese Patent Laid-open No. 2011-128943 discloses a shorearrival assistance device for a boat entering a specific harbor.

The shore arrival assistance device includes a recording device thatrecords the locus from the entrance into the harbor until a shorearrival target position, and boat operating instructions are issued tothe boat operator so as to follow the locus when arriving at the shore.Specifically, during shore arrival, an approach range is determined fromthe locus, and when the position of the boat deviates from the approachrange, an instruction is outputted by the shore arrival assistancedevice to the boat operator so as to return to the final approachstarting point.

However, the shore arrival assistance device can only be used in aspecific harbor for which a locus is recorded in the recording device.In addition, even if the boat is moved without deviating from theapproach range, the boat operation in the vicinity of the shore is noteasy and the boat operator requires high skill to be able to bring theboat to the shore smoothly.

SUMMARY OF THE INVENTION Preferred Embodiments of the Present Invention

provide boats and control methods of the same to facilitate the shorearrival at any harbor.

A boat according to a first preferred embodiment of the presentinvention includes a boat body, a propulsion device, a sensor, and acontroller. The propulsion device is disposed in the boat body andgenerates a propulsion force to move the boat body. The sensor detects ashape of a shore arrival location and a positional relationship of theshore arrival location and the boat body and outputs environmentinformation indicating the shape of the shore arrival location and thepositional relationship. The controller is configured or programmed toreceive the environment information and to generate an instructionsignal to control the propulsion device to cause the boat body to movetoward the shore arrival location based on the environment informationand to push the boat body to the shore arrival location.

In a control method for a boat according to a second preferredembodiment of the present invention, environment information indicatinga shape of a shore arrival location and a positional relationship of theshore arrival location and a boat body is detected. An instructionsignal is generated to control a propulsion device to cause the boatbody to move toward the shore arrival location based on the environmentinformation and to push the boat body to the shore arrival location.

In a preferred embodiment of the present invention, environmentinformation indicating the shape of the shore arrival location and thepositional relationship of the shore arrival location and the boat bodyis detected, and the propulsion device is automatically controlled sothat the boat body moves toward the shore arrival location based on theenvironment information. As a result, the boat is able to arrive at theshore easily even in an unspecified harbor.

In addition, the propulsion device is controlled so as to push the boatbody to the shore arrival location even if the boat body is positionedin a position spaced away from the shore arrival location due to acontrol error or due to wind or a tidal current after the shore arrival.As a result, getting on and off the boat body is facilitated.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a boat according to a preferred embodiment ofthe present invention.

FIG. 2 is a side view of the boat.

FIG. 3 is a side cross-sectional view illustrating a configuration of afirst propulsion device of the boat.

FIG. 4 is a schematic view illustrating a boat operating mechanism and acontrol system of the boat.

FIG. 5 is a flow chart illustrating automatic shore arrival controlprocessing.

FIG. 6 is a flow chart illustrating automatic shore arrival controlprocessing.

FIG. 7 is a flow chart illustrating automatic shore arrival controlprocessing.

FIG. 8 is a flow chart illustrating automatic shore arrival controlprocessing.

FIG. 9 is a view illustrating an operation screen.

FIG. 10 is a view illustrating an input and correction method of atarget position for shore arrival.

FIG. 11 is a view illustrating an input and correction method of atarget position for shore arrival.

FIG. 12 is a view illustrating an automatic setting method of the targetposition for shore arrival.

FIG. 13 is a view illustrating an example of an environment map.

FIG. 14 is a view illustrating a determination method for an offsetamount.

FIG. 15 is a view illustrating a determination method for a targetnavigation route.

FIG. 16 is a view illustrating a control block for determining a targetvelocity and angular speed.

FIG. 17 is a view illustrating a control block for determining a targetpropulsion force and steering angle.

FIG. 18 is a view illustrating the control of the propulsion device in afloating pier mode.

FIG. 19 is a view illustrating the control of the propulsion device in afixed pier mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following is an explanation of boats according to preferredembodiments of the present invention with reference to the drawings.FIG. 1 is a plan view of a boat 1. In FIG. 1, a portion of theconfiguration inside the boat 1 is depicted. FIG. 2 is a side view ofthe boat 1. In the present preferred embodiment, the boat 1 is a jetpropulsion boat, for example, and is a type of boat called a jet boat ora sports boat.

The boat 1 includes a boat body 2, engines 3L and 3R, and propulsiondevices 4L and 4R. The boat body 2 includes a deck 11 and a hull 12. Thehull 12 is disposed below the deck 11. An operator's seat 13 and apassenger seat 17 are disposed on the deck 11.

The boat 1 includes two engines 3L and 3R and two propulsion devices 4Land 4R, for example. Specifically, the boat 1 includes a first engine 3Land a second engine 3R. The boat 1 includes a first propulsion device 4Land a second propulsion device 4R. However, the number of engines is notlimited to two and there may be one engine or three or more engines. Thenumber of propulsion devices is not limited to two and there may be onepropulsion device or three or more propulsion devices.

The first engine 3L and the second engine 3R are contained in the boatbody 2. The output shaft of the first engine 3L is connected to thefirst propulsion device 4L. The output shaft of the second engine 3R isconnected to the second propulsion device 4R. The first propulsiondevice 4L is driven by the first engine 3L to produce a propulsion forceto move the boat body 2. The second propulsion device 4R is driven bythe second engine 3R to produce a propulsion force to move the boat body2. The first propulsion device 4L and the second propulsion device 4Rare disposed side by side to the right and left of each other.

The first propulsion device 4L is a propulsion device that sucks in andjets water around the boat body 2. FIG. 3 is a side view illustrating aconfiguration of the first propulsion device 4L. A portion of the firstpropulsion device 4L is illustrated as a cross-section in FIG. 3.

As illustrated in FIG. 3, the first propulsion device 4L includes afirst impeller shaft 21L, a first impeller 22L, a first impeller housing23L, a first nozzle 24L, a first deflector 25L, and a first reversebucket 26L. The first impeller shaft 21L extends in the front-backdirection. The front portion of the first impeller shaft 21L isconnected to the output shaft of the engine 3L via a coupling 28L. Therear portion of the first impeller shaft 21L is disposed inside thefirst impeller housing 23L. The first impeller housing 23L is disposedbehind a water suction portion 27L. The first nozzle 24L is disposedbehind the first impeller housing 23L.

The first impeller 22L is attached to the rear portion of the firstimpeller shaft 21L. The first impeller 22L is disposed inside the firstimpeller housing 23L. The first impeller 22L rotates with the firstimpeller shaft 21L and sucks in water from the water suction portion27L. The first impeller 22L jets the sucked in water from the firstnozzle 24L to the rear.

The first deflector 25L is disposed behind the first nozzle 24L. Thefirst reverse bucket 26L is disposed behind the first deflector 25L. Thefirst deflector 25L switches the jetting direction of the water from thefirst nozzle 24L to the left and right directions. That is, by changingthe bearing of the first deflector 25L in the left and right directions,the traveling direction of the boat 1 is changed to the left or right.

The first reverse bucket 26L is able to switch between a forward travelposition and a reverse travel position. While the first reverse bucket26L is in the forward travel position, water from the first nozzle 24Land the first deflector 25L is jetted toward the rear. As a result, theboat 1 travels forward. While the first reverse bucket 26L is in thereverse travel position, the jetting direction of the water from thefirst nozzle 24L and the first deflector 25L is changed to the front. Asa result, the boat 1 travels in reverse.

Although omitted in the drawings, the second propulsion device 4Rincludes a second impeller shaft, a second impeller, a second impellerhousing, a second nozzle, a second deflector, and a second reversebucket. The second impeller shaft, the second impeller, the secondimpeller housing, the second nozzle, the second deflector, and thesecond reverse bucket are respectively configured in the same way as thefirst impeller shaft 21L, the first impeller 22L, the first impellerhousing 23L, the first nozzle 24L, the first deflector 25L, and thefirst reverse bucket 26L, and explanations thereof are omitted.

Next, the boat operating mechanism and the control system of the boat 1will be explained. FIG. 4 is a schematic view illustrating the boatoperating mechanism and the control system of the boat 1. As illustratedin FIG. 4, the boat 1 includes a controller 41. The controller 41includes a computation device such as a CPU and a storage device such asa RAM or a ROM, and is programmed so as to control the boat 1.

The boat 1 includes a first engine control unit (ECU) 31L, a firststeering actuator 32L, a first steering control unit (CU) 33, a firstshift actuator 34L, and a first shift control unit (CU) 35L. The aboveelements control the first propulsion device 4L. Each of the first ECU31L, the first steering CU 33L, and the first shift CU 35L include acomputation device such as a CPU and a storage device such as a RAM or aROM, and are configured or programmed so as to control the device towhich they are connected.

The first ECU 31L is communicatively connected to the first engine 3L.The first ECU 31L outputs an instruction signal to the first engine 3L.

The first steering actuator 32L is connected to the first deflector 25Lof the first propulsion device 4L. The first steering actuator 32Lchanges the steering angle of the first deflector 25L. The firststeering actuator 32L is, for example, an electric motor. The firststeering CU 33L is communicatively connected to the first steeringactuator 32L. The first steering CU 33L outputs an instruction signal tothe first steering actuator 32L.

The first shift actuator 34L is connected to the first reverse bucket26L of the first propulsion device 4L. The first shift actuator 34Lswitches the position of the first reverse bucket 26L between theforward travel position and the reverse travel position. The first shiftactuator 34L is, for example, an electric motor. The first shift CU 35Lis communicatively connected to the first shift actuator 34L. The firstshift CU 35L outputs an instruction signal to the first shift actuator34L.

The boat 1 includes a second ECU 31R, a second steering actuator 32R, asecond steering CU 33R, a second shift actuator 34R, and a second shiftCU 35R. The above elements control the second propulsion device 4R andare configured in the same way as the above-described first ECU 31L, thefirst steering actuator 32L, the first steering CU 33L, the first shiftactuator 34L, and the first shift CU 35L, respectively.

The boat 1 includes a steering device 14, a joystick 42, a remotecontrol unit 15, a display 43, an input 44, a positional sensor 45, anda sensing device 46. The steering device 14, the display 43, the input44, the positional sensor 45, and the sensing device 46 arecommunicatively connected to the controller 41, the first and secondECUs 31L and 31R, the first and second steering CUs 33L and 33R, and thefirst and second shift CUs 35L and 35R. For example, the above devicesare connected to each other over a control area network (CAN) or aCAN-FD.

Due to the above devices being connected to each other, the transmissionof information between each of the devices is possible at the same time.Consequently, adjustment control of the steering, shifting, andthrottling are performed easily. In addition, the connections of theabove devices define a duplex system. As a result, stable communicationis maintained.

The remote control unit 15 has an analog connection with the controller41. However, the remote control unit 15 may be connected over the CANnetwork or the like in the same way as the other devices.

The steering device 14 is disposed at the operator's seat 13. Thesteering device 14 includes, for example, a steering wheel. The steeringdevice 14 is operated to steer the boat body 2. The steering device 14outputs operation signals. The first steering CU 33L and the secondsteering CU 33R control the first and second steering actuators 32L and32R in accordance with the operation of the steering device 14.Consequently, the traveling direction of the boat 1 is changed to theleft or right.

The remote control unit 15 is disposed at the operator's seat 13. Theremote control unit 15 is operated to adjust the output of the engines3L and 3R, and to switch between forward and reverse travel. The remotecontrol unit 15 includes a first throttle operating member 15L and asecond throttle operating member 15R. The first throttle operatingmember 15L and the second throttle operating member 15R are, forexample, lever-shaped members.

The remote control unit 15 outputs signals to indicate the operationamount and operating direction of the first and second throttleoperating members 15L and 15R. The first ECU 31L controls the rotationspeed of the first engine 3L in response to the operation amount of thefirst throttle operating member 15L. The second ECU 31R controls therotation speed of the second engine 3R in response to the operationamount of the second throttle operating member 15R.

The first shift CU 35L controls the first shift actuator 34L in responseto the operating direction of the first throttle operating member 15L.The second shift CU 35R controls the second shift actuator 34R inresponse to the operating direction of the second throttle operatingmember 15R. As a result, the travel direction of the boat 1 is switchedbetween forward and reverse travel.

The joystick 42 is disposed at the operator's seat 13. The joystick 42is operated to cause the boat body 2 to move forward and reverse andleft and right. In addition, the joystick 42 is operated to change thebearing of the boat body 2. The operation signals from the joystick 42are inputted to the controller 41. The controller 41 controls the firstand second engines 3L and 3R, the first and second steering actuators32L and 32R, and the first and second shift actuators 34L and 34R. As aresult, the boat 1 moves forward and reverse and to the left and right.Alternatively, the boat 1 is turned to change the bearing.

The display 43 and the input 44 are disposed at the operator's seat 13.The display 43 displays information pertaining to the boat 1. Thedisplay 43 receives display information from the controller 41. Thedisplay 43 displays information in response to the display signals fromthe controller 41.

The input 44 accepts inputs pertaining to the boat 1. The input 44outputs input signals indicating the inputted information. The input 44may be integral with the display 43 and include a touch panel.Alternatively, the input 44 may be separate from the display 43.

The positional sensor 45 detects the current position and the currentbearing of the boat body 2 and outputs position information indicatingthe current position and the current bearing. The positional sensor 45is, for example, an inertial navigation device and includes a globalnavigation satellite system (GNSS) device 47 and an inertial measurementunit (IMU) 48. The GNSS device 47 detects the current position and theboat speed of the boat body 2. The IMU 48 detects the angular speed andthe acceleration of the boat body 2. In addition, the current bearing ofthe boat body 2 is detected by the GNSS device 47 and the IMU 48. Thecurrent bearing may be detected by a plurality of GNSS devices, amagnetic bearing sensor, or an electronic compass.

The sensing device 46 detects the shapes of objects surrounding the boatbody 2 and the positional relationship between the objects and the boatbody 2. The positional relationship between the objects and the boatbody 2 includes the distance between the objects and the boat body 2 andthe direction in which the object is positioned with respect to the boatbody 2. Objects surrounding the boat body 2 include, for example, piers,wharves, other boats, obstructions, or the like.

The sensing device 46 includes one type of sensor or a plurality oftypes of sensors among a radar, a laser, a camera or an ultrasonicsensor. The sensing device 46 may include a plurality of radars, aplurality of lasers, a plurality of cameras, or a plurality ofultrasonic sensors. The radar includes, for example, a millimeter waveradar, a microwave radar, or another radar of a different wavelength.The sensing device 46 detects and outputs environment information duringa below-described automatic shore arrival control.

The environment information indicates the shape of the shore arrivallocation and the positional relationship between the shore arrivallocation and the boat body 2. The environment information may indicatethe shore arrival location or other boats surrounding the boat body 2.The environment information may indicate the shore arrival location orstructures or obstructions surrounding the boat body 2. The environmentinformation is indicated, for example, by coordinates of point groupsindicating the position of an object detected by the sensing device 46.Alternatively, the environment information may be the shape and positionof an object captured by image recognition.

As illustrated in FIG. 4, the sensing device 46 may be connected to theCAN or the CAN-FD through a programmable logic device (PLD) such as afield-programmable gate array (FPGA) 49 or the like. Alternatively, thesensing device 46 may be connected to the CAN or the CAN-FD through adigital signal processor (DSP).

The boat 1 includes an automatic shore arrival function. The automaticshore arrival function automatically enables the boat body 2 to arriveat a shore arrival location such as a pier without operations by theoperator. Hereinbelow, the automatic shore arrival control executed bythe automatic shore arrival function will be explained in detail. FIGS.5 to 8 are flow charts of a process of the automatic shore arrivalcontrol executed by the controller 41.

As illustrated in FIG. 5, the controller 41 obtains current positioninformation from the positional sensor 45 in step S101. The controller41 obtains the current position and the current bearing of the boat body2 in real time from the position information. In step S102, thecontroller 41 evaluates whether the sensing device 46 has captured asensing object. When an object is captured by the sensing device 46, theprocessing advances to step S103. In step S103, the controller 41obtains the environment information from the sensing device 46.

In step S104, the controller 41 or the FPGA 49 recognizes a shorearrival location, another boat, an obstruction, or a surroundingstructure based on the environment information. The shore arrivallocation is, for example, a pier. The controller 41 or the FPGA 49recognizes another boat or an obstruction based on the shape of theobject detected by the sensing device 46. For example, the controller 41or the FPGA 49 recognizes the shore arrival location and the surroundingstructure based on the height and length of the object detected by thesensing device 46.

In step S105, the controller 41 displays an environment map indicatingthe surrounding environment on the display 43. FIG. 9 is a viewillustrating an operation screen 61 of the automatic shore arrivalfunction. As illustrated in FIG. 9, the operation screen 61 is displayedby GUI on the display 43. The operation screen 61 includes anenvironment map 62 and a plurality of operating keys. By pressing theplurality of operating keys, the inputs of the various operations of theautomatic shore arrival function are accepted by the input 44.

The shapes of the shore arrival location, the obstructions, and thesurrounding structures recognized by the controller 41 are displayed onthe environment map 62. While not illustrated in FIG. 9, other boatsrecognized by the controller 41 are also displayed on the environmentmap 62. The controller 41 displays the current position and the currentbearing of the boat body 2 obtained from the position information on theenvironment map 62 with an icon 71 of the boat body 2.

The environment map 62 is updated in real time due to the repeateddetection of the position information by the positional sensor 45 andthe repeated detection of the environment information by the sensingdevice 46. The plurality of operating keys include a scale changing key63. By operating the scale changing key 63, the displayed scale of theenvironment map 62 is enlarged or reduced.

FIG. 6 is a flow chart illustrating processing to set a target positionof the shore arrival. As illustrated in step S201 in FIG. 6, thecontroller 41 determines a possible shore arrival space. The controller41 determines the possible shore arrival space based on the environmentinformation. As illustrated in FIG. 10, the controller 41 determines aposition along the object recognized as the shore arrival location, as apossible shore arrival space SP1. For example, the controller 41 detectsthe disposition of the pier from the environment information anddetermines a predetermined range along the pier as the possible shorearrival space SP1.

Moreover, the controller 41 detects the dispositions of the shorearrival location and of another boat docked at the shore arrivallocation from the environment information, and determines the possibleshore arrival space SP1 from the dispositions of the shore arrivallocation and the other boat. As illustrated in FIG. 10, when two otherboats 201 and 202 are docked with an interval therebetween, thecontroller 41 calculates a distance dl between the two other boats 201and 202. The controller 41 then determines that the space between thetwo other boats 201 and 202 is able to serve as the possible shorearrival space SP1 when the distance dl between the two other boats 201and 202 is greater than a threshold which indicates a space in whichdocking by the host boat is possible.

In step S202, the controller 41 displays the possible shore arrivallocation on the environment map 62. The possible shore arrival locationmay be the above-described possible shore arrival space SP1.Alternatively, the possible shore arrival location may be a specifiedposition inside the possible shore arrival space SP1. The environmentmap 62 on which the possible shore arrival location is displayed may bea bird's-eye view as illustrated in FIG. 9. Alternatively, an imagecaptured by a camera may be displayed as the environment map 62. In thiscase, the possible shore arrival location may be displayed on the imagecaptured by the camera.

In step S203, the controller 41 evaluates whether there is an input ofthe target position for the shore arrival. Here, the input of the targetposition on the environment map 62 is accepted by the input 44. Theoperator touches the possible shore arrival location on the environmentmap 62, such that the touched position is inputted as the targetposition. The input 44 outputs target position information whichindicates the target position to the controller 41.

In step S204, the controller 41 evaluates whether the inputted targetposition is within a suitable range SP2. When the inputted targetposition is within the suitable range SP2, the processing advances tostep S205.

In step S205, the controller 41 corrects the target position. Thecontroller 41 corrects the target position based on the possible shorearrival space SP1. For example, as illustrated in FIG. 10, when aninputted target position IP1 is outside of the possible shore arrivalspace SP1, the controller 41 corrects a target position Tp so that thetarget position is within the possible shore arrival space SP1. When aninputted target position IP2 is inside the possible shore arrival spaceSP1, the controller 41 corrects the target position Tp so that thetarget position becomes the center position of the possible shorearrival space SP1.

As illustrated in FIG. 9, the operation screen 61 includes a targetposition setting key 64. When the target position setting key 64 ispressed, the operator is able to manually input any position withoutbeing limited to the space SP1. Therefore, the touched position isreceived as the target position by the input 44. In this case, when theposition spaced away from the shore arrival location in a directionperpendicular or substantially perpendicular to the direction along theshore arrival location is inputted as the target position, thecontroller 41 may correct the target position to a position along theshore arrival location. At this time, as illustrated in FIG. 11, thetarget position Tp is preferably corrected to a position closest to theinputted target position IP3 within the position along the shore arrivallocation.

When there is no input of the target position in step S203, theprocessing advances to step S206. For example, when a touch of theenvironment map 62 has not been detected for a predetermined timeperiod, the processing advances to step S206.

In step S206, the controller 41 automatically sets the target position.Here, as illustrated in FIG. 12, the controller 41 sets the closestposition in the current bow direction among the positions along theshore arrival location, as the target position.

In step S207, the controller 41 evaluates whether a pushing mode hasbeen turned on. As explained hereinbelow, the pushing mode is a controlfor controlling the propulsion devices 4L and 4R so as to push the boatbody to the shore arrival location. For example, a setting screen forthe pushing mode may be invoked by pressing a menu key 69 on theoperation screen 61 illustrated in FIG. 9, whereby setting for turningthe pushing mode on or off is made possible. In this case, the input 44functions as a mode setter to accept an input to turn the pushing modeon or off.

The pushing mode includes a floating pier mode and a fixed pier mode.The floating pier mode, as illustrated in FIG. 18, is a control thatcontrols the propulsion devices 4L and 4R so as to push the boat body toa floating pier 301 floating on the water surface. The fixed pier mode,as illustrated in FIG. 19, is a control that controls the propulsiondevices 4L and 4R so as to push the boat body to a fixed pier 302 thatis fixed to another surface. Selection of the fixed pier mode and thefloating pier mode may be possible in the above-described pushing modesetting screen. In this case, the input 44 functions as a mode selectorto accept the selection of the fixed pier mode and the floating piermode.

In step S207, when the floating pier mode is turned on, the processingadvances to step S208. In step S208, the controller 41 resets the targetposition. The controller 41, as illustrated in FIG. 18, resets, as thetarget position, the position TP′ which is spaced away from the targetposition TP set in step S205 or step S206 by a predetermined distance inthe direction from the boat body 2 to the floating pier 301. Thepredetermined distance may be set as a value which is small enough sothat the docked boat body 2 is not separated from the floating pier 301.

In step S207, when the fixed pier mode is not turned on, the processingadvances to step S209.

In step S209, the controller 41 displays the target position and thetarget bearing with an icon 71′ on the environment map 62. Here, asillustrated in FIG. 9, the controller 41 sets the target positioncorrected in step S205 or the target position automatically set in stepS206 as the target position, and displays the icon 71′ which indicatesthe host boat in the position on the environment map 62. The icon 71′ isdisplayed in the target bearing determined by the controller 41 in theinitial state. The controller 41 determines the target bearing of theboat body 2 based on the shape of the shore arrival location, thecurrent bearing, the distance to the target position, or the like. Forexample, when the shore arrival location is a pier, the controller 41determines a direction along the edge of the shore arrival location asthe target bearing. Alternatively, the controller 41 may determine adirection that defines a predetermined angle with the direction alongthe edge of the shore arrival location, as the target bearing. Moreover,the controller 41 may change the target bearing in response to thecurrent bearing or the distance to the target position.

As illustrated in FIG. 9, the operation screen 61 includes a firstbearing changing key 65 and a second bearing changing key 66. The targetbearing is changed by a predetermined angle (for example, about 90° at atime) each time the first bearing changing key 65 is pressed. However,the unit angle for the changing is not limited to 90° and may be smallerthan 90° or greater than 90°. The second bearing changing key 66 isrotatably provided on the operation screen 61. The target bearing ischanged in response to the rotation of the second bearing changing key66. The bearing of the icon 71′ of the host boat on the environmentscreen is changed in response to the change of the target bearing.

When the inputted target position is not within a suitable range SP2 instep S204, the target position is not corrected and the inputted targetposition is set as the target position. For example, as illustrated inFIG. 10, the suitable range SP2 is a range that includes the possibleshore arrival space SP1. When the inputted target position IP4 isoutside of the suitable range SP2, the target position is not corrected.Therefore, when the inputted target position IP4 is spaced away from thepossible shore arrival space SP1 by a predetermined distance or more,the inputted target position is not corrected and is set as the targetposition. The size of the suitable range SP2 is set to a value that isable to be determined when a position spaced away from the possibleshore arrival space SP1 is intentionally touched without the targetposition input being shifted.

As illustrated in FIG. 9, the operation screen 61 includes an automaticshore arrival mode start button 67 and an automatic shore arrival modestop button 68. As indicated above, after the target position has beenset, the automatic shore arrival control is started when the operatorpresses the automatic shore arrival mode start button 67. When theautomatic shore arrival control is started, the controller 41 generatesinstruction signals to control the propulsion devices 4L and 4R so thatthe boat body 2 arrives at the target position. Hereinbelow, theprocessing to start and end the automatic shore arrival control will beexplained.

As illustrated in step S301 in FIG. 7, the controller 41 evaluateswhether the automatic shore arrival control has started. When theautomatic shore arrival mode start button 67 is pressed, the processingadvances to step S302. In step S302, the controller 41 evaluates whetherthe boat 1 has reached a second target position.

As illustrated in FIG. 13, with the target position and the targetbearing determined in above-described steps S201 to S207 beingestablished as the first target position TP1, the second target positionTP2 is a position spaced away from a first target position TP1 by apredetermined offset amount on the current position side of the boat 1.In the automatic shore arrival control, the controller 41 firstlycontrols the propulsion devices 4L and 4R so that the boat 1 reaches thesecond target position TP2, and then controls the propulsion devices 4Land 4R so that the boat 1 reaches the first target position TP1. Thesecond target position TP2 is explained below.

When the boat 1 has not reached the second target position TP2 in stepS302, the processing advances to step S303. In step S303, the controller41 evaluates whether a position error and a bearing error are equal toor less than first thresholds. The position error is the distancebetween the current position of the boat body 2 and the second targetposition TP2. The bearing error is the difference between the currentbearing of the boat body 2 and the target bearing. When the distancebetween the current position of the boat body 2 and the second targetposition TP2 is equal to or less than a first position threshold, andthe difference between the current bearing of the boat body 2 and thetarget bearing is less than a first bearing threshold, the controller 41determines that the position error and the bearing error are equal to orless than the first thresholds. When the position error and the bearingerror are not equal to or less than the first thresholds, the processingadvances to step S304.

In step S304, the controller 41 determines the second target positionTP2. As illustrated in FIG. 14, the controller 41 calculates the bearingdifference between the current bearing and the target bearing, anddetermines an offset amount L of the first target position TP1 inresponse to the bearing difference. The controller 41 determines aposition spaced away by the offset amount from the first target positionTP1 on the current position side as the second target position TP2. Thatis, the controller 41 determines a position spaced away by the offsetamount L from the first target position TP1 in the directionperpendicular or substantially perpendicular to the edge of the shorearrival location, as the second target position TP2. Specifically, whenthe shore arrival location is a pier, the controller 41 uses thefollowing equation 1 to determine the offset amount.

L=a×|Heading_err/90|+b+W  Equation 1

L is the offset amount. a is a predetermined coefficient and isdetermined based on the distance between the center of gravity and thebow of the boat body 2. The Heading_err is the bearing differencebetween the current bearing and the first target bearing as illustratedin FIG. 14. However when the Heading_err is equal to or greater than90°, the Heading_err is set to 90°. b is a margin corresponding to theboat body 2 with respect to the target bearing and the direction alongthe edge of the shore arrival location. W is the width of another boat.

That is, the controller 41 calculates the bearing difference between thecurrent bearing and the target bearing and calculates the margin thatcorresponds to the boat body 2. The controller 41 determines the offsetamount L of the first target position TP1 in response to the bearingdifference and the margin that corresponds to the boat body 2.

Therefore, the controller 41 increases the offset amount in response tothe size of the bearing difference Heading_err. The controller 41determines the offset amount based on the distance between the center ofgravity and the bow of the boat body 2. The controller 41 determines theoffset amount so as to be greater than the width W of another boatdocked at the shore arrival location. The offset amount is calculatedand updated in real time.

As illustrated in FIG. 13, when an obstruction X1 is present between thefirst target position TP1 and the current position, the controller 41determines the second target position TP2 so as to avoid theobstruction. Specifically, as illustrated in FIG. 15, a grid is providedon the environment map 62. The controller 41 determines the secondtarget position TP2 by excluding the grid within a predetermined rangefrom the obstruction X1.

In addition, the controller 41 determines a target navigation route Ph1to the second target position TP2. The controller 41 establishes theshortest route to the second target position TP2 within the route thatpasses through the set grid, as the target navigation route Ph1. At thistime, when an obstruction is present, the controller 41 determines thetarget navigation route Ph1 by excluding the grid within thepredetermined range from the object recognized as the obstruction. Thedetermined target navigation route Ph1 is displayed on the environmentmap 62. The controller 41 calculates and updates the target navigationroute Ph1 in real time.

The disposition of the grid is set so that a predetermined number ofgrids are disposed between the current position of the boat body 2 andthe target position. Therefore, when the distance between the boat body2 and the target position is changed, the disposition of the grid ischanged.

As shown in step S305 in FIG. 7, the controller 41 changes the targetposition from the first target position TP1 to the second targetposition TP2.

When the position error and the bearing error are equal to or less thanthe first thresholds in step S303, the processing advances to step S306.That is, the processing advances to step S306 when the current positionis near the second target position TP2 and the current bearing is nearthe target bearing without the boat 1 having completely reached thesecond target position TP2.

In step S306, the controller 41 determines a target speed and a targetangular speed from the target position and the target bearing.

When the boat 1 has not yet entered a predetermined range from thesecond target position TP2 (“No” in S303), the controller 41 sets thesecond target position TP2 as the target position and determines thetarget speed and the target angular speed. When the boat 1 has enteredthe predetermined range from the second target position TP2 (“Yes” inS302 or S303), the controller 41 sets the first target position TP1 asthe target position and determines the target speed and angular speed.

As illustrated in FIG. 16, the controller 41 calculates a relative errorPb_err from the target position and the current position and from thetarget bearing and the current bearing, and determines a target speedand angular speed Vc based on the relative error Pb_err. The controller41 reduces the target speed and angular speed Vc in response to areduction in the relative error Pb_err. That is, the controller 41reduces the target speed as the current position of the boat body 2approaches the target position. The controller 41 reduces the targetangular speed as the current bearing of the boat body 2 approaches thetarget bearing. When the distance between the current position of theboat body 2 and the target position enters a predetermined range thatincludes zero, the controller 41 sets the target speed to zero.Moreover, when the difference between the current position of the boatbody 2 and the target position enters the predetermined range thatincludes zero, the controller 41 sets the target angular speed to zero.

The relative error Pb_err includes a first position error Pb_err_x, asecond position error Pb_err_y, and a bearing error Pb_err_θ. The firstposition error Pb_err_x is the distance between the target position andthe current position in the front-back direction of the boat body 2. Thesecond position error Pb_err_y is the distance between the targetposition and the current position in the left-right direction of theboat body 2. The bearing error Pb_err_θ is the difference between thetarget bearing and the current bearing.

The target speed and angular speed Vc includes a first target speedVc_x, a second target speed Vc_y, and a target angular speed ωc. Thefirst target speed Vc_x is the target speed in the front-back directionof the boat body 2. The second target speed Vc_y is the target speed inthe left-right direction of the boat body 2. The target angular speed ωcis the target angular speed of the boat body 2.

The controller 41 stores first target speed information Ivcx, secondtarget speed information Ivcy, and target angular speed information Iωc.The first target speed information Ivcx defines the relationship betweenthe first position error Pb_err_x and the first target speed Vc_x. Thesecond target speed information Ivcy defines the relationship betweenthe second position error Pb_err_y and the second target speed Vc_y. Thetarget angular speed information Iωc defines the relationship betweenthe bearing error Pb_err_θ and the target angular speed ωc. The abovesets of information Ivcx to Iωc may be represented, for example, bymaps, tables, numerical calculations, or equations, etc.

The controller 41 determines the first target speed Vc_x from the firstposition error Pb_err_x based on the first target speed informationIvcx. The controller 41 determines the second target speed Vc_y from thesecond position error Pb_err_y based on the second target speedinformation Ivcy. The controller 41 determines the target angular speedωc based on the target angular speed information Iωc.

Alternatively, the target speed and angular speed Vc may be determinedwith the following equation 2. Any of the first position error Pb_err_x,the second position error Pb_err_y, the bearing error Pb_err_θ, theactual speed Vx in the front-back direction of the boat body 2, theactual speed Vy in the left-right direction, and the actual angularspeed co may be used as inputs.

$\begin{matrix}{{Vc} = {\begin{pmatrix}{Vc\_ x} \\{Vc\_ y} \\{\omega \; c}\end{pmatrix} = {f\left( {{{Pb\_ err}{\_ x}},{{Pb\_ err}{\_ y}},{{Pb\_ err}{\_\theta}},{Vx},{Vy},\omega} \right)}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

As shown in step S401 in FIG. 8, the controller 41 evaluates whether thedistance from the current position to the target position is equal to orless than a predetermined threshold Dt1. When the distance to the targetposition is not equal to or less than the predetermined threshold Dt1,the processing advances to step S402. In step S402, the boat body 2 iscontrolled using an approach control. In the approach control, thecontroller 41 determines a target propulsion force and a target steeringangle of the propulsion devices 4L and 4R based on the first targetspeed Vc_x and the target angular speed ωc.

When the distance from the current position to the target position isequal to or less than the predetermined threshold Dt1 in step S401, theprocessing advances to step S403. In step S403, the boat body 2 iscontrolled using an adjust control. In the adjust control, the targetpropulsion force and the target steering angle of the propulsion devices4L and 4R are determined based on the first target speed Vc_x, thesecond target speed Vc_y, and the target angular speed ωc.

In this way, when the distance to the target position is greater thanthe predetermined threshold Dt1, the target position and the targetbearing are reached promptly under the approach control. When thedistance to the target position is equal to or less than thepredetermined threshold Dt1, the boat body 2 is able to be brought tothe target position with high accuracy under the adjust control.

In step S402 and step S403, the controller 41 calculates a force causedby an outside disturbance and determines the target propulsion force andthe target steering angle of the propulsion devices 4L and 4R inconsideration of the force of the outside disturbance. The outsidedisturbance includes, for example, the tidal current or the wind.Fluctuations in the resistance to the boat body caused by weightfluctuations and the like are included in the calculated results.Specifically, the controller 41 determines the target propulsion forceand the target steering angle based on the force of the outsidedisturbance, the target speed, and the target angular speed. FIG. 17 isa control block diagram for determining the target propulsion force andthe target steering angle.

As illustrated in FIG. 17, the controller 41 includes an outsidedisturbance observer 411 and a target propulsion force and steeringangle computing unit 412. The outside disturbance observer 411calculates an outside disturbance force w based on the actual speed andangular speed V of the boat body 2, the actual engine rotation speed n1of the first engine 3L, the actual engine rotation speed n2 of thesecond engine 3R, the actual steering angle δ1 of the first propulsiondevice 4L, and the actual steering angle δ2 of the second propulsiondevice 4R. The actual speed and angular speed V of the boat body 2includes the actual speed Vx in the front-back direction of the boatbody 2, the actual speed Vy in the left-right direction, and the actualangular speed co.

The target propulsion force and steering angle computing unit 412calculates a target propulsion force based on the target speed andangular speed Vc, the actual speed and angular speed V of the boat body2, and the outside disturbance force w. The controller 41 estimates theoutside disturbance force w using the following equation 3.

{dot over (V)}=f _(model)(Vx,Vy,ω,n1,n2,δ1,δ2)

w={dot over (V)}−{dot over ({circumflex over (V)})}  Equation 3

f_(model) is a motion equation of the boat body 2. {dot over (V)} is thetime derivative of V. {dot over ({circumflex over (V)})} is anestimation using the motion equation of the boat body 2.

The controller 41 uses the motion equation represented in the followingequation 4 to calculate a target propulsion force based on, for example,the Lyapunov theory of stability.

{dot over (V)}=f _(model)(Vx,Vy,ω,n1,n2,δ1,δ2)+w  Equation 4

The target propulsion force and steering angle computing unit 412determines a target rotation speed nc1 of the first engine 3L and thetarget rotation speed nc2 of the second engine 3R from the targetpropulsion force. The controller 41 generates an instruction signalcorresponding to the target rotation speed nc1 of the first engine 3Land outputs the instruction signal to the first ECU 31L. The controller41 generates an instruction signal corresponding to the target rotationspeed nc2 of the second engine 3R and outputs the instruction signal tothe second ECU 31R.

Moreover, the target propulsion force and steering angle computing unit412 determines a target steering angle δc1 of the first propulsiondevice 4L and a target steering angle δc2 of the second propulsiondevice 4R based on the target speed and angular speed Vc, the actualspeed and angular speed V of the boat body 2, and the outsidedisturbance force w. The controller 41 generates an instruction signalcorresponding to the target steering angle δc1 of the first propulsiondevice 4L and outputs the instruction signal to the first steering CU33L. The controller 41 generates an instruction signal corresponding tothe target steering angle δc2 of the second propulsion device 4R andoutputs the instruction signal to the second steering CU 33R.

As illustrated in step S404 in FIG. 8, the controller 41 evaluateswhether the position error and the bearing error are equal to or lessthan second thresholds. Specifically, when the distance between thecurrent position of the boat body 2 and the target position is equal toor less than a second position threshold, and the difference between thecurrent bearing of the boat body 2 and the target bearing is equal to orless than a second bearing threshold, the controller 41 determines thatthe position error and the bearing error are equal to or less than thesecond thresholds. The second position threshold is set to a value lessthan the above-described offset amount.

When the position error and the bearing error are equal to or less thansecond thresholds, the processing advances to step S405.

In step S405, the controller 41 evaluates whether the fixed pier modehas been turned on. When the fixed pier mode is turned on, theprocessing advances to step S406. As illustrated in S406 in FIG. 19, thecontroller 41 generates an instruction signal for the propulsion devices4L and 4R to as to produce a boat speed or thrust in the direction fromthe boat body 2 toward the fixed pier 302, in the target position TP.The controller 41 also controls the propulsion devices 4L and 4R so thatthe produced boat speed or thrust is maintained. The boat speed or thethrust produced at this time may be set to a value that is low enough sothat the docked boat body 2 is not separated from the fixed pier 302.

When the pushing mode is turned off, that is, when both the floatingpier mode and the fixed pier mode are turned off, the controller 41controls the propulsion devices 4L and 4R so as to stop the boat body 2at the target position set in step S205 or step S206. When an automaticshore arrival mode stop key 68 in FIG. 9 is pressed, the controller 41ends the automatic shore arrival control.

In the boat 1 according to preferred embodiments of the presentinvention explained above, the environment information indicating theshape of the shore arrival location and the positional relationship ofthe shore arrival location and the boat body 2 is detected, and thepropulsion devices 4L and 4R are automatically controlled so that theboat body 2 moves toward the shore arrival location based on theenvironment information. As a result, the boat 1 is able to arrive atthe shore easily even in an unspecified harbor.

In addition, the propulsion devices 4L and 4R are controlled so as topush the boat body 2 to the shore arrival location when the pushing modeis turned on even when the boat body 2 is in a position spaced away fromthe shore arrival location due to a control error or due to the wind orthe tidal current after the shore arrival. As a result, getting on andoff the boat body 2 is facilitated.

In particular, when the floating pier mode is turned on, the controller41 controls the propulsion devices 4L and 4R so that the boat body 2 ismoved to the target position reset in step S208. As a result, asillustrated in FIG. 18, even when the floating pier 301 moves away fromthe original position due to being pushed by the boat body 2, thepropulsion devices 4L and 4R are able to be controlled so as to push theboat body 2 to the floating pier 301 by a predetermined distance.

When the fixed pier mode is turned on, the controller 41 controls thepropulsion devices 4L and 4R so that the boat body 2 is moved to thetarget position set in step S205 or step S206. The controller 41 thencontrols the propulsion devices 4L and 4R so that a boat speed or thrustis produced in the direction from the boat body 2 toward the shorearrival location in the target position. As a result, the propulsiondevices 4L and 4R are able to be controlled so as to push the boat body2 to the fixed pier 302.

Although preferred embodiments of the present invention have beendescribed so far, the present invention is not limited to the abovepreferred embodiments and various modifications may be made within thescope of the invention.

The boat 1 is not limited to a jet propulsion boat and may be anothertype of boat. For example, the boat 1 may be a boat provided withoutboard motors that includes propellers driven by the engines 3L and3R. That is, the propulsion devices 4L and 4R are not limited to jetpropulsion devices and may be another type of propulsion device such asan outboard motor.

The automatic shore arrival control may be executed in a predeterminedlow-speed region. For example, the automatic shore arrival control maybe executed when the boat speed is a predetermined set speed or less.

The correction method for the target position of the shore arrival maybe changed. Alternatively, the correction of the target position may beomitted. The method for determining the second target position may bechanged. That is, the method for determining the offset amount may bechanged. Alternatively, the setting of the second target position may beomitted. The method for estimating the outside disturbance may bechanged. Alternatively, the estimation of the outside disturbance may beomitted.

Either one of the fixed pier mode and the floating pier mode may beomitted. The selection to turn off the fixed pier mode, the floatingpier mode, or the pushing mode may be switched automatically in responseto the surrounding environment information. For example, the above modesmay be switched in accordance with the distance to the pier.

The variables in the motion equation of the boat body 2 may be changedor other variables may be added. For example, while the state variablesof the motion equation of the boat body 2 in the above preferredembodiments are the actual speed Vx in the front-back direction, theactual speed Vy in the left-right direction, and the actual angularspeed co of the boat body 2, the variables may be changed or othervariables may be added. For example, the state variables may bevariables indicating the position and attitude of the boat body 2 suchas the position in the front-back direction, the position in theleft-right direction, the bearing, the pitch angle, or the roll angle ofthe boat body 2. While the variables of the motion equation in the abovepreferred embodiments are the actual engine rotation speeds n1 and n2,and the actual steering angles δ1 and δ2, the variables may be increasedor reduced in response to the number of propulsion devices.

According to preferred embodiments of the present invention, the boat isable to arrive at the shore easily even in an unspecified harbor.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1-14. (canceled)
 15. A boat comprising: a boat body; a propulsion devicedisposed in the boat body and that generates a propulsion force to movethe boat body; a sensor that detects a shape of a shore arrival locationand a positional relationship between the shore arrival location and theboat body, and that outputs environment information indicating the shapeof the shore arrival location and the positional relationship; and acontroller configured or programmed to receive the environmentinformation and to generate an instruction signal to control thepropulsion device so as to move the boat body toward the shore arrivallocation based on the environment information, and to push the boat bodyto the shore arrival location.
 16. The boat according to claim 15,wherein the controller is configured or programmed to generate theinstruction signal so as to produce a boat speed or a thrust in adirection from the boat body toward the shore arrival location.
 17. Theboat according to claim 15, further comprising: a display that displaysan environment map indicating the shape of the shore arrival location;and a position input that accepts an input of the shore arrival locationon the environment map; wherein the controller is configured orprogrammed to generate the instruction signal so as to move the boatbody to the shore arrival location based on the input to the positioninput, and to produce a boat speed or a thrust in a direction from theboat body toward the shore arrival location.
 18. The boat according toclaim 15, further comprising: a display that displays an environment mapindicating the shape of the shore arrival location; a position inputthat accepts an input of the shore arrival location on the environmentmap; wherein the controller is configured or programmed to: reset, asthe shore arrival location, a position spaced away by a predetermineddistance from the shore arrival location based on the input to theposition input in a direction from the boat body toward the shorearrival location; and generate the instruction signal so as to move theboat body to the reset shore arrival location.
 19. The boat according toclaim 15, further comprising: a display that displays an environment mapindicating the shape of the shore arrival location; a position inputthat accepts an input of the shore arrival location on the environmentmap; and a mode setter that accepts an input to turn on or off a pushingmode that controls the propulsion device so as to push the boat body tothe shore arrival location; wherein the controller is configured orprogrammed to: generate the instruction signal so as to move the boatbody to the shore arrival location based on the input to the positioninput, and to stop at the shore arrival location when the pushing modeis turned off; and generate the instruction signal so as to move theboat body toward the shore arrival location and to push the boat body tothe shore arrival location when the pushing mode is turned on.
 20. Theboat according to claim 15, further comprising: a display that displaysan environment map indicating the shape of the shore arrival location; aposition input that accepts an input of the shore arrival location onthe environment map; and a mode selector that accepts a selection of afixed pier mode and a floating pier mode in a pushing mode that controlsthe propulsion device so as to push the boat body to the shore arrivallocation; wherein the controller is configured or programmed to:generate the instruction signal so as to move the boat body to the shorearrival location based on the input to the position input and to producea boat speed or a thrust in a direction from the boat body toward theshore arrival location when the fixed pier mode is selected; and reset,as the shore arrival location, a position spaced away by a predetermineddistance from the shore arrival location based on the input to theposition input, in the direction from the boat body toward the shorearrival location, and to generate the instruction signal so as to movethe boat body to the reset shore arrival location when the floating piermode is selected.
 21. The boat according to claim 20, wherein thecontroller is configured or programmed to switch selection of the fixedpier mode, the floating pier mode, and the pushing mode to off based onthe environment information.
 22. A control method for a boat comprising:detecting environment information indicating a shape of a shore arrivallocation and a positional relationship between the shore arrivallocation and a boat body; and generating an instruction signal tocontrol a propulsion device so as to move the boat body toward the shorearrival location based on the environment information, and to push theboat body to the shore arrival location.
 23. The control method for aboat according to claim 22, wherein the instruction signal is generatedso as to produce a boat speed or a thrust in a direction from the boatbody toward the shore arrival location.
 24. The control method for aboat according to claim 22, the method further comprising: displaying anenvironment map indicating the shape of the shore arrival location; andaccepting an input of the shore arrival location on the environment map;wherein the instruction signal is generated so as to move the boat bodyto the shore arrival location based on the input, and to produce a boatspeed or a thrust in a direction from the boat body toward the shorearrival location.
 25. The control method for a boat according to claim22, the method further comprising: displaying an environment mapindicating the shape of the shore arrival location; and accepting aninput of the shore arrival location on the environment map; andresetting, as the shore arrival location, a position spaced away by apredetermined distance from the shore arrival location based on theinput in a direction from the boat body toward the shore arrivallocation; wherein the instruction signal is generated so as to move theboat body to the reset shore arrival location.
 26. The control methodfor a boat according to claim 22, the method further comprising:displaying an environment map indicating the shape of the shore arrivallocation; and accepting an input of the shore arrival location on theenvironment map; and accepting an input to turn on or off a pushing modethat controls the propulsion device so as to push the boat body to theshore arrival location; wherein the instruction signal is generated soas to move the boat body to the shore arrival location based on theinput of the shore arrival location, and to stop at the shore arrivallocation when the pushing mode is turned off; and the instruction signalis generated so as to move the boat body toward the shore arrivallocation and to push the boat body to the shore arrival location whenthe pushing mode is turned on.
 27. The control method for a boataccording to claim 22, the method further comprising: displaying anenvironment map indicating the shape of the shore arrival location; andaccepting an input of the shore arrival location on the environment map;and accepting a selection of a fixed pier mode and a floating pier modein a pushing mode that controls the propulsion device so as to push theboat body to the shore arrival location; wherein the instruction signalis generated so as to move the boat body to the shore arrival locationbased on the input of the shore arrival location, and to produce a boatspeed or a thrust in a direction from the boat body toward the shorearrival location when the fixed pier mode is selected; and the methodfurther comprises: resetting, as the shore arrival location, a positionspaced away by a predetermined distance from the shore arrival locationbased on the input in the direction from the boat body toward the shorearrival location, and the instruction signal is generated so as to movethe boat body to the reset shore arrival location when the floating piermode is selected.
 28. The control method for a boat according to claim27, further comprising: switching selection of the fixed pier mode, thefloating pier mode, and the pushing mode to off based on the environmentinformation.